ADSORPTION OF PHOSPHATIDYLCHOLINE LIPOSOMES AT THE AIR-WATER-INTERFACE

Adsorption kinetics of a purified lecithin, dioleylphosphatidylcholine (DOPC) were studied at different temperatures and ionic strengths (pure water, 0.15M NaCl, and 5M NaCl) by the Wilhelmy plate technique. The effects of particle size (by sonication) and morphological modifications (by osmotic deflation) were assessed. The initial kinetic constantsK obtained by a methodology derived fromWard and Tordaï(Recueil71, 572 (1952)) show very large differences between the batches. Pure water and 5M media induce wide variations in liposomal adsorption rates, the latter most certainly by polar head dehydration. Changes in morphology from spherical to deformable shape (osmotic deflated liposomes) increased initial adsorption rates 40 times. The adsorption of fluid-state lecithin liposomes can thus be interpreted in a similar way to interliposomal fusion. © 1991 Academic Press, Inc. All rights reserved.